<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
    <meta name="author" content="林镭特">
    <title></title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        main{
            width: 350px;
            display: flex;
            height: 50px;
            text-align: center;
            line-height: 50px;
            background-color: darkgray;
            margin: 0 auto;
        }
        div{
            width: 80px;
            position: relative;
        }
        div:hover{
            text-decoration: underline;
            color: yellow;
        }
        ul{
            font-size: 12px;
            width: 60px;
            list-style: none;
            position: absolute;
            left: 0;
            top: 50px;
            border: 1px solid gainsboro;
            display: none;
            color: gainsboro;
            
        }
        ul li:hover{
            text-decoration: underline;
        }

    </style>
</head>
<body>
    <main>
        <div>
            公司简介
            <ul>
                <li>概况介绍</li>
                <li>发展历史</li>
                <li>公司实力</li>
            </ul>
        </div>
        <div>
            产品介绍
            <ul>
                <li>概况介绍</li>
                <li>发展历史</li>
                <li>公司实力</li>
            </ul>
        </div>
        <div>
            联系我们
            <ul>
                <li>概况介绍</li>
                <li>发展历史</li>
                <li>公司实力</li>
            </ul>
        </div>
        <div>
            人才招聘
            <ul>
                <li>概况介绍</li>
                <li>发展历史</li>
                <li>公司实力</li>
            </ul>
        </div>
    </main>
    <script src="jQuery.js"></script>
<script>
      $('div').hover(function () {
          console.log('asd');
        $(this).find('ul').show();
    },function () {
        $(this).find('ul').hide();
    })
</script>
</body>
</html>